1. Field of the Invention
The invention relates to a guide bushing between two components that are axially movable relative to each other, especially for guiding a piston rod subjected to longitudinal and transverse forces of a hydropneumatic vibration damper.
2. Description of the Related Art
A guide bushing of this type is disclosed, for example, in German reference DE 29 05 928 A1. In this reference, the guide bushing is pressed into the piston rod guide. The pressure joint in which the guide bushing is received requires expensive precision working within strict tolerances, and an equally precise production of the guide bushing, to ensure that an accurate pressure seat is created. At the same time, sticking of the piston rod in the guide must be prevented and the gap between the guide bushing and the piston rod must be maintained below a certain limit. In serial manufacture of a plurality of these parts, relatively large differences in the size of this gap lead to wide damping force variations, which are not acceptable to vehicle manufacturers. To reduce these variations in damping force, it is known to use an additional sealing ring that is axially movable between two stops. This is expensive to produce and to assemble and does not lead unconditionally to the desired success.
Further, another reference DE 195 01 792 A1 discloses a piston with a piston ring, wherein the piston ring has a width greater than the axial extension of the outer cylindrical surface of the piston. Therefore, there is an overlap of the piston ring on the outer cylindrical surface. The piston ring is drawn securely onto the piston and has no clearance relative to the piston in either the radial or the axial movement direction.